Glass fiber compositions



i No Drawing.

continuous filament" glass.

. J This glass has aworkable liquidus temperature, and

, 3,16 6,42 GLASS FIBER co osITIoNs George L. Thomas, Parma, Ohio, assignor to The B. F.

Goodrich Company, New York, N.Y., a corporation of New York 7 Claims. (01106-60) r This application is a continuation-in-part of, my copending application Serial Number 102,673, filed April 13, 1961, and now abandoned.

Thisinvention relates to a glass composition which is Filed July. 11, 1963, Ser. No. 294,239

United States Patent especially suitable for the manufacture of glass fibers of high Youngs modulus and high tensile strength. The

glassficomposition of this invention has fiber spinning "properties comparable to a sodium calcium silicate glass and ,also the boro silicate glass composition commonly knownin the trade as E glass, yet, fibers spun from this .new 'glasscomposition-have'an aver-age tensile strengthof V atleast 30%. to 50% greater thanrthe tensile strength of E. glass fibers of corresponding gauge.

fibers, as shown in High Modulus Glass Fibers-for Structunal Plastics, The Glass lndustry,'December 1960, page Because of the substantial improvement in ,l tensile strength compared to' 'E glass fibers of corresponding gauge; fibers made from the glass composition .OilihlS invventiorrare especially useful for the manufactiiiebf glass reinforced plastic, articles and particularly filament wound 1 'sglass plastic pressure yessels. Moreover, laminates of these higHstr engthQgIassf fibersin-ia plastic matrix have been found to, be atleast 30%; "to 50%, better in flex,

strength than corresponding identical laminates prepared with commercially available E glassfibers.

The glass composition disclosed can be melted, formed into marbles, remelted and drawn into fibers by convenused materials finds ready While I have succeeded in making a glass composition The art recognized standard for high strength glass that have too short a working range.

amaizs ice long spinning range, slow rate of crystallization,- and increased Youngs modulus may be made in the following compositional range.

Ingredient: Proportion Si0 l -56 L.. K O+Na O 0-10 Alkaline earth oxide 2 4-15 ZnO 0-10 Sb O 0-10 vA1 05 25-35 1 With the sum of Li O+K2O+Na2O always equal to 1-11.

2 wherein the alkaline earth oxide is selected from the group consisting of CaO, MgO, and CaO+MgO wherein when it is CaO-l-MgO, the ratio of CaO to MgO is at least 9,21.

it" is to be notedthat this'is an aluminum silicate glass,

an unusual type to employfor a spinning glass. Asis common in glass technology, the ingredients are given. above in terms ofoxides of the elements. The

compounds may actually be added to the glass-batch in several different forms, however. Lithium, potassium and sodium may be added as carbonates, ascari'calcium and magnesium, p 7 U V Thefalkali oxide is employed as a flux in .the glass'. Lithia has a small ,ionicjra dius and relatively high field strength for alkali ions." It is an essential ingredient of the glass and must always be present in an amount equal tq-at least 1 percent by weight of the batch. Litliia can range up to 11 percent by weight ofthebatch, but higher amounts of alkali oxide than 11 percent lead to glasses Potassium oxide 14 0mm soda (Na O) ,may bewused as part of the alkali oxide used tomake myglass tohelp Hurting properties but there must always be at least, l-percentby weight oflithia andthe total of Li oei-K ot-Na o must not exceed 11 percent by weight of .;the batch. Thealkafound that if botli are usedin the same batch, the weight 1 means that while l cantadd 'therCaOfand M-gO inthe line earth oxi es, .calcia and'magnesia are both useful separately in thepreparation of my glass, but I have ratio of CaQWtoMgO is preferably at least 9: 1. This forms of the carbonate,--=as mentioned above, I can-not use dolomite or dolomiticli riestonei which is essentially CaM-,g(C0 I have found that dolomite, whereinCaO- and MgO are present in an equimolar ratio, givesme glass es much lower in tensile strength than the 'glassiot' mymven'tion. The same is true of any approximately equimolar mixtureof calcium and magnesium that may of extremely high tensile strength, my glasscomposition alsohas good. spinning characteristics fondrawing into It has a' longworklng range of approximatelyZSOF. v

My new glass exhibits a Youngs modulus of about 13x10? p.s.i.. in the uhcompacted fiber which is an im-- .pressive increase over the modulus of commercial continuous filament fiber-v'glass which is about 11x10 psi.

can be spun under brdinary spinning conditions without be employedm ordinary ealcitic limestone is primarily *calcium carbonate'and nearly always contains some magnesium carbonate as animpurity. If the limestone contains less than101weight percent of magnesium carbonate, fit 'canbe used in preparing the glassbatch of myinvention; Either CaO or MgO' may bevused separately in glassbatchesbut when they are used together, the m-ag- ..nesiuin =must not exceed 1.0% by weight of the calcium.-

, Zinc'oxide is a stal ilizing and surface hardening agent.

Antimony oxide-improves hqmogeneity of the glass by reducing gas bubbles and acts to improve the working propertiesof the glass. j l a Ihehigh'alurnina content of this. glass is believed to be a. primary cause of the-high tensile strength developed.

Incorporating such high amounts of alumina in a glass is difficult, since it tends to cause devitrification at the low temperatures employed for spinning. The successful result'sjl have achieved are vbelieved to. befdue to the the use of special nozzles; cooling or handling and withhigh alumina content}? 1 out devitritication which is quiteunexpected because of its t :LThe great strength ofmy glass, whenit is drawnlinto ;--fibers.or filaments, is believed to be duelrto its] specific compositional range A glass .withhigh tensilest rength,

use of lithia and the correct proportioning of the remain- "iiig constituentsl 7 V The glass of thisinvention; when drawninto fibers, hasj atensile strength superior to that of commercially available filament glasses and in improv ed Youngs \modulu'sn It melts readily inexistingglass melting units,

Patented Jan, 19, 1965 V of the test glass is reported as percent: of the control.

. In. another evaluation test for my' glass fibers, I pr e-' 7 resin This .is a low viscosity, 0 '140: s. at c- Batches Fire; I V I ;;positions,; lrf1elted in a small clay or. pla'tinumic'rucible units.

amasse To compare various batches of my glass with each other and with continuous filament E glass, I have emat 2550-2650 F. and formed into marbles. The marbles are remelted in platinumbushings and drawn into single filament and 204 filament form. The filaments are processed as described above. Glass compositions and test rate or 5,000 feet per minute; and a' length of approximately 10"of filament is cut from thesection between the nozzle and the drawing wheel during spinning; The

Sample is mounted on a cardboard containing 5 one inch openings along the length of the-filament. The filament "ends overlapping the end of the'cardboard are removed and checked for diameter under; a microscope. They V should'agree Within 0.00002 inch. The filament is glued i V openings to-give' 5 one inch lengths' of filament which'can 'be mounted in an Instron Testing ;Machine for tensile test. "Withevery filament or group of filaments a control taken 351001.311 arbitraryvalue) and the tensilevstrength pare fiber-resinlaminatesl .jThe firstjstep in forming these laminates .is to prepare unidirectional mats by (winding;

the glass filarnents on arotating drum and spraying them' with aplastic re'sin'ql The'resin employed is. an epoxy resin containing 09-72%, non-volatile matter and assay- -ing 350400 g./g. moleepoxy groups. The resin is applied to theglass fiber'by 'sprayingjfrom a solveritholution. Anl amine catalyst hardener is mixed with the resin solution and 'initiates the partial cure P of g the resin in".

'ployed a single filament tensile test as follows: 5 data are summarized in T able 1. Standard E glass, em-

The glass batch is mixed, melted, formed into cullet, ployed as the control, is melted and drawn through the reme'lted in a single hole platinum bushing and drawn same nozzles as the test glasses and at thesarn'e drawing "through a single platinum nozzle. The samenozzle is speeds. v r i Talile l V p EXAMPLES 1- 10 g Control 1 2 3 4 -5 0 7 8 I 9 10 0.0 2.0 0.9 1.0 A1203 33.2 30.0 31.3 28.5 Youngs modulus p.s'.i. l0 11.0 13.0 12.4. 12.8 12.9 Single filament 130 130 138 Tensile strength, percent of cont 1 1 5 Laminate flex. strength, p.s.i 220,000 r 291, 000 250,000 e90, 000 282,000 Laminate mod. of elasticity, p.s.i. 10 8.7 10. 7' 9. 5 w 10. 6 .10. 3 I Percent of resin in laminateby weight... 10.4 11.0 10.7 14.7 11.5 V i v employed in all cases. The filament is drawn at the 25 Comparison of these data indicates that glasses 1-5.

from my new glass and plastic. resins than from presently available fiber glass. Example 6 shows the negative effect of employing diolomitic limestoneto provide the alkaline earth ingredients. Example] is made with l0y2 percent *filament'of' commercial E glass is run. The control is the matrixon the drum. The unidirectional mats are Youngsmodulus is run on the uncompacted'fiberlby I r a standard sjonicmethod utilizing measurement of the speed of sound transmitted through the glassL This .methodis de'scribed in J. AppxPhysics 20,1493 (1949). a

j 'The' glass composition of my invention is illustrated by the 'follo'wing exampleswhere'iri the ingredients are' proportioned 'byweight. Continuous. filamentfcomm'en cial E glassisused as theicontr ol inall'test's run.

- XAMPLES 1 10 mjx'ed' to give the, following oxide ee'mbuilt up of glass fiber andv resin to a thickness of about I 0.010 ;inch and contain 10-20 by' weight of I'resinJ V "Enough layers of matare plied together, with the fibers still unidirectional, to for na stiff 'laminatefsheetabout 1 'to,;% inch thick after compaotionfandfinal cure in' lithia. The high-amount 'of alkali oxide gives" the glass a short workingrange. Example 9shows the use of C'aO alone asthe alkaline earthoxide ingredient. Examples Sand 10 show the use ot MgO aloneafs the alkaline earth oxide ingredient.

' I claim:

l1. Aluminum 'silcate glass fibers iconsi stin always"equal to 21.7-10.2.

' consisting of .yCaO,

V CaOelMgO wherein when 3 both CaO and Mg O are emg gq ployed, the; ratio of 0310 to MgO is at least 921.

Alkaline an oxi -Q- 2. Aluminurn'silicateglass"fibersconsisting in percent 7 y; g f e SiO 44.0-55.3

consisting. of Li O elected frorn the group and said glass fibers having an average tensile strength at least 30% greater than the tensile strength of E glass fibers of corresponding gauge.

3. An aluminum silicate glass fiber consisting essentially in percent by weight of:

Si 55.3 Li O 5.5 Na O 0.9 K 0 0.9 MgO 4.3 2110 0.9 Sb O 0.9 A1203;

said glass fiber having an average tensile strength at least 30% greater than the tensile strength of E glass fibers of corresponding gauge.

4. An aluminum silicate glass fiber consisting essentially in percent by weight of:

Si0 51.1 Li O 6.2 0210 7.9 M30 0.6 A1 0 34.2

said glass fiber having an average tensile strength at least 30% greater than the tensile strength of E glass fibers of corresponding gauge.

5. An aluminum silicate glass fiber consisting essentially in percent by Weight of:

said glass fiber having an average tensile strength at least 30% greater than the tensile strength of E glass fibers of corresponding gauge.

6. An aluminum silicate glass fiber consisting essentially in percent by Weight of:

sio 48.1 Li O 4.9 Na O 1.9 K 0 3.3 0210 7.4 MgO 0.6 Sb O 0.6 A1203 said glass fiber having an average tensile strength at least 30% greater than the tensile strength of E glass fibers of corresponding gauge.

7. An aluminum silicate glass fiber consisting essentially in percent by weight of:

SiO 49.5 Li O 6.3 CaO 9.5

MgO 0.7 A1 0 34 0 said glass fiber havng an average tensile strength at least 30% greater than the tensile strength of E glass fibers of corresponding gauge.

References Cited by the Examiner UNITED STATES PATENTS 2,685,527 8/54 Labino 106-50 3,044,888 7/62 Provance 10650 3,095,311 6/63 Von Wranau et a1 106-50 FOREIGN PATENTS 124,553 6/47 Australia.

551,326 1/58 Canda.

902,563 12/44 France.

765,244 1/ 57 Great Britain.

OTHER REFERENCES Karkhavavale et al.: J. Am. Cer. Soc.; December 1953, Reactions in the System Li OMgO--Al O SiO :I, The Cordierite-Spodumene Join (page 394).

Lajarte: German Appl. 1,088,675, printed September 8, 1960 (K1. 32b 1).

TGBIAS E. LEVOW, Primary Examiner. 

1. ALUMINUM SILICATE GLASS FIBERS CONSISTING IN PERCENT BY WEIGHT OF; 